It is earlier known to fasten buttons to textile materials or similar without recurring to any sewing operation by fastening a projecting portion of the button to the material by means of riveting or a corresponding operation. The projection can in itself be designed to be formed to a rivet head, which cannot penetrate the material and holds the button, but there are also buttons designed with the head as a separate part, which is snapped-on or riveted to the head portion of the button. It has also been suggested in connection with such buttons that several buttons should be fastened simultaneously by way of example a whole row of buttons on a piece of garment, and it has been suggested that the projections should be inserted in the button holes corresponding to the respective cooperating buttons before the fastening. Thus, after the fastening operation the piece of garment would be buttoned up. In many cases it is preferred to deliver the garment for sale in buttoned-up condition, and if the buttons are fastened in a condition with their projections stretching through the buttonholes, a special buttoning-up operation is thus not necessary.